NEW YORK (Reuters) - One in five adults in the United States, or nearly 50 million people, suffered mental illnesses in 2010, with women and young adults suffering disproportionately, a government report released on Thursday found.

The survey by the Substance Abuse and Mental Health Services Administration found women were more likely than men (23 percent versus 16.8 percent) to have experienced a mental illness, while the rate of mental illness among people aged 18 to 25 was twice that of those aged 50 and older.

The survey found that 5 percent of American adults, or 11.4 million people, surveyed in 2010 had suffered a serious mental illness in the past year that substantially interfered with their lives.

According to the report, about 8.7 million American adults had serious thoughts of suicide in the past year, with 2.5 million making suicide plans and 1.1 million attempting to take their own lives.

Americans suffering mental illnesses were three times more likely to have developed substance dependence or substance abuse disorders than adults who had not experienced mental illness.

Among youths aged 12 to 17, 8 percent -- or 1.9 million teenagers -- experienced a major depressive episode in the past year, defined as a period of at least 2 weeks when a person experienced a depressed mood or loss of interest.

Those teenagers who experienced a depressive episode also had twice the rate of illicit drug use than teenagers who had not experienced depression.

The administration surveyed 67,500 people aged 12 and older in person around the United States.